Search Publications
An Upper Limit to the Mass of the Radial Velocity Companion to ρ1 Cancri
Han, Inwoo; Gatewood, George; Black, David C. +7 more
Doppler spectroscopy of ρ1 Cnc has detected evidence of a companion with an orbital period of 14.65 days and a minimum mass of 0.88 Jupiter masses. Astrometric observations performed with the Hubble Space Telescope Fine Guidance Sensor 1r using a novel observing technique have placed an upper limit on the astrometric reflex motion of ρ<…
Radio Galaxies at z = 1.1 to 3.8: Adaptive Optics Imaging and Archival Hubble Space Telescope Data
Hutchings, J. B.; Crampton, D.; Steinbring, E.
We have undertaken a program of high-resolution imaging of high-redshift radio galaxies (HzRGs), using adaptive optics on the Canada-France-Hawaii Telescope. We report on deep imaging in J, H, and K bands of six HzRGs in the redshift range 1.1 to 3.8. At these redshifts, near-infrared bandpasses sample the rest-frame visible galactic light. The ra…
An Impulsive Solar Flare Accompanied by a Cusplike Structure in Soft X-Rays
Grechnev, V. V.; Nakajima, H.
A detailed analysis of an impulsive solar flare of 1999 September 17 was carried out using microwave, soft, and hard X-ray data. The flare showed pronounced nonthermal processes and was accompanied by a cusplike structure in soft X-rays in the decay phase, manifesting features attributed to different flare models. The results suggest that importan…
Relationship between horizontal flow velocity and cell size for supergranulation using SOHO Dopplergrams
Singh, Jagdev; Paniveni, U.; Krishan, V. +1 more
A study of 90 supergranular cells obtained from SOHO Dopplergrams was undertaken in order to investigate a possible relation between the sizes and peak horizontal velocities of the cells. For the sample obtained, the two parameters are found to be correlated with a relation: horizontal velocity ~(size)1/3. This is in agreement with the …
Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos. I. Comparison with known orbits
Gontcharov, G. A.; Kiyaeva, O. V.
Complementing the Proper Motions of Fundamental Stars catalogue by Gontcharov et al. (CDS, I-266) the photocentric orbits of some FK5/Hipparcos stars are calculated in a direct combination of the Hipparcos data with astrometric ground-based observational catalogues having epochs later than 1939. Some capabilities and limitations of this method are…
A high-resolution study of the evolution of the Lyman alpha forest in the redshift interval 0.9 < z < 1.7
Reimers, D.; Janknecht, E.; Baade, R.
Spectroscopy with HST/STIS Echelle and VLT/UVES of the bright QSO HE 0515-4414 (zem =1.73, B = 15.0) offers for the first time the opportunity to study the Lyman alpha forest in the redshift range 0.9 < z < 1.7 at a resolution <=10 km s-1. The number density evolution of the Lyman alpha lines is well described by the…
Relation between dust and radio luminosity in optically selected early type galaxies
Jaffe, W.; Krajnović, D.
We have surveyed an optical/IR selected sample of nearby E/S0 galaxies with and without nuclear dust structures with the VLA at 3.6 cm to a sensitivity of 100 mu Jy. We can construct a Radio Luminosity Function (RLF) of these galaxies to ~ 1019 W Hz-1 and find that ~ 50% of these galaxies have AGNs at this level. The space de…
Observations of Quasar Hosts with Adaptive Optics at Lick Observatory
Graham, James R.; Lacy, Mark; Lloyd, James P. +4 more
We present near-infrared H-band observations of the hosts of three z~1 quasars from the Sloan Digital Sky Survey made with the adaptive optics system at Lick Observatory. We derive a point-spread function (PSF) for each quasar and model the host plus quasar nucleus to obtain magnitudes and approximate scale sizes for the host galaxies. We find our…
The Solar Origin of the 6 January 1997 Coronal Mass Ejection
Dai, Y.; Tang, Y. H.; Wu, Y. Q. +1 more
By using observations from the satellites of the International Solar Terrestrial Physics (ISTP) Observatories, the relationships among the coronal mass ejection (CME), the helmet streamer and the disappearing filament (DSF) have been studied. Our main conclusions are as follows: (1) The DSF disrupted the streamer, thus resulting in the restructuri…
Multiwavelength optical observations of chromospherically active binary systems. IV. The X-ray/EUV selected binary BK Psc (2RE J0039+103)
Montes, D.; López-Santiago, J.; Cornide, M. +3 more
We present high resolution echelle spectra taken during four observing runs from 1999 to 2001 of the recently X-ray/EUV selected chromospherically active binary BK Psc (2RE J0039+103). Our observations confirm the single-lined spectroscopic binary (SB1) nature of this system and allow us to obtain, for the first time, the orbital solution of the s…